▼OL. XII.5 PHILOSOPHICAL TRANSACTION!, S77 



very pretty motion, often tumbling about and sideways; and when the water 

 was to let to run off from them, they turned round like a top; at first their 

 body changed into an oval, and afterwards, when the circular motion ceased, 

 they returned to their former length. The second sort of creatures discovered 

 m this water, were of a perfect oval figure, and they had no less pleasing or 

 nimble a motion than the former; and these were in far greater numbers. There 

 was a third sort, which exceeded the two former in number, and these had tails 

 like those I had formerly observed in rain-water. The fourth sort, which 

 moved through the three former sorts, were incredibly small, so that I judged, 

 that if 100 of them lay one by another, they would not equal the length of a 

 grain of coarse sand; and according to this estimate, 1,000,000 of them could 

 not equal the dimensions of a grain of such coarse sand. There was disco- 

 vered a fifth sort, which had near the thickness of the former, but almost twice 

 the length. 



In snow-water, which had been about three years in a glass bottle well 

 stopped, I could discover no living creatures; and having poured some of it 

 into a porcelain tea-cup, and put therein half an ounce of whole pepper, after 

 some days I observed some animalcula, and those exceedingly small ones, whose 

 body seemed to me twice as long as broad, but they moved very slowly, and 

 often circularly. I observed also a vast multitude of oval-figured animalcula, 

 to the number of 6000 or 8000 in a single drop. 



Some Observations, made by Sig. Cassini, concerning the two Planets about Sa- 

 turn, formerly discovered by him, as appears in N° Q2 of these Tracts, N° 1 33, 

 p. 831. 



One of these two planets, which is distant from the centre of Saturn 10 dia- 

 meters and a half of his ring, makes its revolution about Saturn in 80 days. It 

 was discovered at the Parisian Observatory, anno 1671, about the end of Oct. 

 and in the beginning of Nov. in his greatest occidental digression, and after many 

 cloudy days it ceased to appear, for a reason which was then unknown, but has 

 since been discovered. For, after many revolutions of this small planet had been 

 observed, it was found to have a period of apparent augmentation and diminu- 

 tion, by which period it becomes visible in its greatest occidental digression, 

 and invisible in its greatest oriental elongation. 



Hence it seems, that one part of its surface is not so capable of reflecting to 

 us the light of the sun as the other part is. Whence we may conjecture, that 

 the globe of this satellite has some diversity of parts, analogous to that of the 

 earth, the one part of whose surface is covered by the sea, which is not so fit 

 to reflect from all parts the light of the sun, as the continent which makes up 



VOL. II. ' 3 C 



